What are melanoidins, polymers in food?

Abstract

Melanoidins are brownish heterogeneous high-molecular-weight compounds formed at the final stage of the Maillard reaction. Louis C. Maillard found that brownish polymer was formed in a reaction solution containing amino acids and reducing sugars and called those pigments melanoidins, which resulted that melanoidins have become known as the Maillard reaction end products. Melanoidins are formed during the processing and storage of various kinds of food, causing a significant influence on the quality of foods. For instance, melanoidins cause some changes in not only the color of foods but also odor and texture and show antioxidative activities and dietary fiber-like properties. The formation mechanism and the chemical structure of melanoidins are not understood fully, because of complexity and heterogeneity. However, they are being comprehended gradually through the great efforts by many scientists. Melanoidins are formed by the polymerization of a variety of reactants and intermediate products of the Maillard reaction and by cross-linking between proteins through low-molecular-weight pigments. Therefore, analyses of low-molecular-weight pigments formed by the Maillard reaction may result in the clarification of melanoidins in more detail.